Trichoderma harzianum

About: Trichoderma harzianum is a research topic. Over the lifetime, 4731 publications have been published within this topic receiving 96796 citations.

Strategies for large scale inoculum development for solid state fermentation system: conidiospores of Trichoderma harzianum.

Abstract: The suitability of disc fermenter for efficient production of conidiospores by Trichoderma harzianum is limited to a working capacity of 0.61 agar medium due to large decrease in spore production per cm2 of the culture surface area with further increase in the capacity. In contrast, Zymotis, a large scale solid state fermenter designed at ORSTOM, France and use of inert solid support for absorbing nutrients offer many advantages for production of conidiospores in quantity sufficient enough to inoculate pilot and larger fermenters. Five times higher production of conidiospores in Zymotis, as compared to the agar medium in flask, constitutes a success in the development of large scale inoculum.

Effect of benomyl and benomyl resistance on cellulase formation by Trichoderma reesei and Trichoderma harzianum

Abstract: To investigate the possible relationship between resistance to benomyl and the production of cellulases by Trichoderma spp., we investigated the effect of benomyl on growth and cellulase formation in Trichoderma reesei, Trichoderma harzianum, and the benomyl-resistant mutant T. harzianum T95. While T. reesei produced the highest and T. harzianum the lowest cellulase amounts, growth of both strains was equally inhibited by 2 μg/mL benomyl. However, sublethal doses of benomyl (0.2–0.5 μg/mL) promoted growth, stimulated cellulase production, and produced a highly branched, crippled morphology. The same phenomenon was observed with T. harzianum T-95, albeit at higher (5–10 μg/mL) benomyl concentrations. Introduction of the Neurospora crassa ben gene, coding for a benomyl-resistant β-tubulin, into a T. reesei by transformation yielded a series of transformants, which exhibited increased growth, increased cellulase formation, and highly branched, crippled morphology. Key words: Trichoderma harzianum, Trichoderm...

In vitro biocontrol analysis of Alternaria alternata (Fr.) Keissler under different environmental conditions.

Abstract: The species Trichoderma harzianum was analyzed as possible biocontrol agent of Alternaria alternata under different environmental conditions (water activity and temperature). The strains were analyzed macroscopically to obtain the Index of Dominance. The analysis was completed using two microscopic techniques. T. harzianum showed dominance on contact over A. alternata at all testing temperatures and water activities tested except at 0.95 a(w) and 15 degrees C, at which T. harzianum inhibited A. alternata at a distance. Biocontrol was governed by different mechanisms such as competition for space and nutrients, mycoparasitism, and possible antibiosis. Temperature and water activity significantly influenced fungal growth rate.

Availability of phosphorus and sulfur of insecticide origin by fungi

Abstract: Thirteen fungal species isolated from soil treated with pesticides were tested for their ability to mineralize and degrade three organophosphate insecticides currently used in Egypt (Cyolan®, Malathion® and Dursban®) in liquid media free from phosporus (P) and sulfur (S). All fungal species grew successfully on the culture media treated with the three used doses of insecticides (10, 50 and 100 ppm active ingredient) but the growth rate varied with the species, the insecticide and the doses. At 10 ppm level, insecticide degradation expressed in term of organic P mineralization (calculated as % of applied P) was the highest with all fungi tested. Organic P mineralization from pesticides was decreased by increasing the dose used to 50 and 100 ppm. The highest amount of P mineralized was observed with Cyolan® followed by Malathion® whilst P mineralization from Dursban® proceeded very slowly. Aspergillus terreus showed the greatest potential to mineralize organic P followed by A. tamarii, A. niger, Trichoderma harzianum and Penicillium brevicompactum whilst the remaining fungi only moderately mineralized the organic P component of the insecticides tested. Organic sulfur mineralization by the used fungal species paralleled, to some extent, organic P mineralization. The extracellular protein content of culture filtrates in the presence of various doses of insecticides was also decreased by increasing insecticide concentrations. The extracellular protein was significantly correlated with P and S mineralization (r = 0.89** and 0.64**, respectively) whilst correlation with cell dry mass was not significant (r = 0.03 and 0.003) suggesting a direct relationship between pesticide degradation and microbial protein production. The addition of P or S to the growth media enhanced extracellular protein excretion, and increased organic P and S mineralization by the most potent species tested (A. niger, A. tamarii, A. terreus and T. harzianum). This increment was significant in most cases, especially at the higher application rates. The relationship between extracellular protein excretion and organic P and S mineralization from insecticides was highly significant with the addition of inorganic phosphorus (r = 0.96** and 0.83**, respectively) or sulfur (r = 0.85** and 0.89**, respectively) to the growth media.

Effects of some Iranian Trichoderma isolates on maize seed germination and seedling vigor

Abstract: Trichoderma species are commonly used as biological control agents against phytopathogenic fungi and some of their isolates are able to improve plant growth. In the current study, we evaluated some Iranian Trichoderma isolate cultural filtrates as well as their direct effect on seed germination and seedling vigor of maize (Zea mays L. cultivar B73); they are Trichoderma harzianum T 969, T. harzianum T 447, Trichoderma hamatum T 614, Trichoderma roseum T678, Gliocladium virens G525 and the unknown Trichoderma species isolate (Trichoderma sp. T) obtained from the soil of Moghan Area, Ardabil Province of Iran. The culture filtrates reduced the speed of seed germination, but no influence (p
0.05) was recorded at the final rate of the seed germination. When maize seeds were exposed to the Trichoderma spore suspension, all the Trichoderma isolates colonized the seed surface and inhibited the seed germination. The maize seed potted in inoculated soil did not emerge from the soil among all tested Trichoderma isolates, except for non-inoculated soil 30 days after potting. When Trichoderma conidia were added on the surface of soil near the emerged seed, significant (p0.01) decrease of seedling treated separately with T. hamatum T614 isolate was observed on the leaves area, fresh root and shoot weight, compared to the non-inoculated seedling. Whereas T. hamatum T447 and T. harzianum T969 reduced markedly (p0.01), seedling fresh root weight and fresh shoot weight were respectively increased as compared to the control. Trichoderma isolates had no influence on chlorophyll content in leaves and root length as well as stomata conductivity, except for Trichoderma spp. isolate T that increased stomata conductivity of seedling significantly (p0.01).